1. Field of the Invention
Embodiments of the present invention generally relate to uninterruptible power supplies. More particularly, embodiments of the present invention relate to controlling power distribution from an uninterruptible power supply based upon the power demand of one or more attached devices.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art which may be related to one or more aspects of the present invention as described and claimed below. This discussion is believed helpful in providing the reader with background information, thereby facilitating a better understanding of various aspects of the present invention. Accordingly, it should be understood by the reader that the provided information should be read in this light and not as an admission of prior art.
Uninterruptible power supplies (“UPS”) are often used to condition the power supplied to electrical appliances, computers, computer peripherals and the like. Uninterruptible power supplies can also provide a limited duration or back-up power source in the event of a failure of the primary power source. Traditionally, almost every UPS includes several common components: an incoming alternating current power source, a fast acting bypass contactor, one or more batteries, one or more rectifiers to convert a portion of the incoming AC power to DC power, and one or more inverters to convert the DC power supplied by the batteries to AC power. Various additional features can be added to a UPS, for example one or more power conditioners can be added to the AC bypass through the UPS to filter any voltage spikes or sags in the power source. Additionally, overcurrent protection devices, such as fuses and/or circuit breakers can be added to the incoming power source to guard against damage to the UPS from an overcurrent condition on the primary power source.
Uninterruptible power supplies can have multiple power distribution outlets. These distribution outlets can be UPS backed, non-UPS backed, conditioned, filtered, protected, or any combination thereof. Placing more than one type of power distribution outlet on a single UPS permits, for example, plugging a computer CPU into a UPS backed outlet, a monitor into a conditioned or filtered, non-UPS backed outlet, and one or more peripherals such as printers, scanners, desk lamps, etc. into simple: AC pass-through outlets in a single, convenient location.
The power consumption of a typical desktop personal computer CPU can vary widely, ranging from about 50 watts to 700 watts while in operation. To reduce power consumption during periods of inactivity, many CPUs are equipped with energy conservation software or firmware. The Advanced Configuration and Power Interface (“ACPI”) is a typical energy conservation firmware, providing a variety of “states” in accordance with the level of CPU activity. ACPI provides multiple, reduced power consumption, “sleep” states. In one or more ACPI sleep states, the power consumption of the CPU is substantially reduced by powering down the CPU, cache, chipset and, peripherals. Often the RAM is placed into a low-power, self-refreshing mode to further conserve power. However, despite power conservation efforts within the CPU, often one or more peripherals such as printers, scanners, desk lamps, etc. remain at full power draw, thereby minimizing the energy savings. While the power demand of the CPU can be directly addressed using firmware such as ACPI, the various peripherals used in conjunction with the CPU continue to draw power even though the CPU may be in an inactive, reduced power, “sleep” state.
There is a need, therefore, for improved systems and methods for reducing the power consumption of one or more peripherals typically used in conjunction with a personal computer when the computer CPU enters one or more reduced power demand states.